The robot did not cover a planned drive of 50 feet (15 meters), instead chalking up about 36 feet (11 meters).

But the rover moved far enough down the road to get in good position to acquire a full high-resolution mosaic of Vera Rubin Ridge (VRR) over the weekend, reports Mark Salvatore, a planetary geologist at the University of Michigan in Dearborn.

“In addition, Curiosity parked herself in a nice sandy location where we can continue to investigate sand ripples on our way towards the ridge,” Salvatore adds. The science team has planned a full weekend of scientific investigations and data collection.

On the schedule, Curiosity’s Chemistry and Camera (ChemCam) will kick off this weekend’s science plan by investigating the chemistry of two of the few rocky targets in front of the rover: “Zephyr Ledges,” the multi-toned flaky patch of rocky material surrounded by sand ripples, and “Wallace Ledge,” which is a more massive piece of rock a bit further from the rover.

Curiosity Mastcam Left image taken on Sol 1788, August 17. 2017.Credit: NASA/JPL-Caltech/MSSS

Two rocky targets

Following these chemistry measurements, the robot’s Mastcam will be used to document these two rocky targets, including a multispectral observation of “Zephyr Ledges” and the surrounding sands, Salvatore explains.

“Multispectral observations collect images at more wavelengths than our eyes are accustomed to viewing, which allows us to detect ‘color’ variations that help us to decipher the composition of these different materials,” Salvatore says.

ChemCam will also collect a high-resolution image mosaic of VRR from this location before Sol 1790’s first block of scientific investigations is completed. The second science block of Sol 1790 will be dedicated exclusively to collecting a twelve image mosaic of VRR using Mastcam.

Curiosity Mastcam Right image taken on Sol 1788, August 17, 2017.Credit: NASA/JPL-Caltech/MSSS

Essential mosaics

Salvatore points out that these mosaics are essential to understand the structure of the ridge as can be seen from this perspective. “Once we are up on VRR itself, we will be unable to see these subsurface layers in the same context.”

Late in the afternoon on Sol 1790, Curiosity will unfurl its robotic arm and begin a chemistry analysis of a sand ripple named “The Shivers” using the Alpha Particle X-Ray Spectrometer (APXS) instrument.

“This measurement will last several hours, as the X-rays and alpha particles are generated by the slow radioactive decay of curium within the instrument. The longer the APXS is put in contact with a sample of interest, the more precise the chemical measurement will be,” Salvatore explains.

Ripple effects

Following the measurement of The Shivers, the robot’s APXS will then be moved to another sand ripple target known as “Trumpet,” where it will remain overnight to collect several additional hours of chemical analyses.

“As has been commonly seen in Gale crater, sand ripples exhibit differences in both color and grain size, even over very short distances,” reports Salvatore. “These variations provide really valuable information about wind patterns, the size of particles that can be moved by the wind, and whether there is any difference in composition between sediments of different grain sizes. Both “The Shivers” and “Trumpet” exhibit such differences in color and grain size, which is why they are targets of investigation for this weekend’s science plan.”

Salvatore explains that on Sol 1791, Curiosity will focus on monitoring the local environment in Gale crater. Standard measurements of the local weather and radiation environment will be made, as well as passive sky observations using ChemCam.

“Mastcam will be employed to image the distant rim of Gale crater, as a means of determining how dusty the martian atmosphere is on this day. These measurements are extremely valuable for several reasons, including understanding whether the martian atmosphere will hinder our ability to study the surface both from the ground and from orbit,” Salvatore adds.

Planned drive ahead

On Sol 1792, the scripted plan calls for Curiosity to head off on a planned drive of over 130 feet (40 meters) drive to the east-southeast along the planned VRR ascent route.

After the drive, Curiosity is slated to acquire Navcam and Mascam images of the rover’s immediate surroundings for the science team to use in their planning efforts on Monday morning. As always, the Mars Descent Imager (MARDI) will also acquire an image from below the rover.

Credit: NASA/JPL-Caltech/University of Arizona

Shallow sand bars

“Thinking back to the two rocky targets being investigated on the first day of this weekend plan, “Zephyr Ledges” and “Wallace Ledge,” I can’t help but think of how perfect these names are at this stage of the mission,” Salvatore recalls. “On Earth, these two names correspond to shallow sand bars off the east coast of Maine, in the shallow ocean near more prominent islands that rise above the water.”

Lastly, as Curiosity starts to make preparations to ascend Vera Rubin Ridge, “you can imagine the shallow sand sea that Curiosity is currently exploring and looking up towards the more prominent ridge just to the south,” Salvatore adds. “Take away the mighty Atlantic Ocean, and I wouldn’t be surprised if the hike from one of these shallow sand bars up to a nearby island doesn’t feel similar to Curiosity’s upcoming ascent from the lower Murray formation up into Vera Rubin Ridge,” he concludes.

New road map

Meanwhile, a new Curiosity traverse map through Sol 1789 has been issued.

The map shows the route driven by NASA’s Mars rover Curiosity through the 1789 Martian day, or sol, of the rover’s mission on Mars, as of August 18, 2017.

Numbering of the dots along the line indicate the sol number of each drive. North is up. The scale bar is 1 kilometer (~0.62 mile).

From Sol 1788 to Sol 1789, Curiosity had driven a straight line distance of about 61.76 feet (18.83 meters), bringing the rover’s total odometry for the mission since landing in August 2012 to 10.66 miles (17.16 kilometers).

The base image from the map is from the High Resolution Imaging Science Experiment Camera (HiRISE) onboard NASA’s Mars Reconnaissance Orbiter.